1. Field of the Invention
The present invention relates to a magnetoresistive effect (MR) element for reading a signal representing a magnetic field intensity in a magnetic recording medium, to a thin-film magnetic head with an MR read head element, and to a magnetic disk drive apparatus with the thin-film magnetic head.
2. Description of the Related Art
In order to satisfy demand for higher recording density and downsizing in a hard disk drive (HDD) apparatus, higher sensitivity and larger output of a thin-film magnetic head are required. In order to meet this requirement, a thin-film magnetic head with a giant magnetoresistive effect (GMR) read head element has been put to practical use and a thin-film magnetic head with a tunnel magnetoresistive effect (TMR) read head element is now achieved to come into practical use.
In the thin-film magnetic head with such GMR read head element or TMR read head element, it is now tried to more narrow a space between lower and upper shield layers, that is a read gap, of the read head element in order to attain a higher density recording.
Each of US Patent Publication No. 2004/0207960 A1 and U.S. Pat. No. 7,365,949 B2 discloses a GMR thin-film magnetic head with a decreased thickness over its whole area by extending a pinned layer toward a height direction directed opposite to the air bearing surface (ABS) so as to fix a magnetization direction of the pinned layer with the help of shape anisotropy, and by positioning a pinning layer or anti-ferromagnetic layer at the outside in the height direction of a region in which a free layer, a non-magnetic layer and the pinned layer are arranged.
However, it was insufficient to fix the magnetization direction of the pinned layer only with the help of shape anisotropy. Also, it was difficult to stably fix the magnetization direction of the pinned layer under the influence of magnetic bias from magnetic domain control layers located near the pinned layer.